import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import App from './App';
import reportWebVitals from './reportWebVitals';
let app: any
ReactDOM.render(<App ref={node => app = node} />, document.getElementById('root'), () => {
  console.log(app)
  // app.componentWillUnmount()
  // 通过上面拿到实例对象app
  //通过实例对象拿到节点
  console.log(ReactDOM.findDOMNode(app))
})

// If you want to start measuring performance in your app, pass a function
// to log results (for example: reportWebVitals(console.log))
// or send to an analytics endpoint. Learn more: https://bit.ly/CRA-vitals
reportWebVitals();
